The main cause of facial sagging such as nasolabial folds face lines & the corners of the mouth is relaxation of facial muscles due to aging. Just like the muscles in your body your cheek muscles will weaken if you don't use them. The cheek muscles are the foundation that supports the entire skin & as these muscles weaken the skin sag giving the appearance of aging. Train your facial muscles with the PAO exercise which involves holding a fitness bar in your mouth & shaking it.